TPD Data

Automatic Watch Winder TPD Setting

• What the number countsTurns per day is the total number of rotations a winder applies to a watch across 24 hours. It is a cumulative total, not a speed — the same figure can be delivered in a few long cycles or many short ones, with rest in between.
• The usual rangeMost automatic movements sit between 650 and 950. Across the 750 movements listed here the values run from 395, for a small ladies calibre, to 950. A few movements outside this reference need up to 1,800.
• It is a range, not a targetA published figure is the motion generally sufficient to keep a movement wound, arrived at by observation rather than calculation. Landing near it is the point. Being fifty turns either side of it is not a fault, and hitting it exactly is not an achievement.
• More is not betterOnce the mainspring is charged, extra turns are absorbed rather than stored — so a higher setting buys nothing. Watch Care covers why, along with what stopping does and does not mean.

Winding Direction

Direction is listed beside every figure in the tables above because it changes what a given number of turns is worth.

• Uni-directionalThe mainspring winds when the rotor turns one way and not the other, so only part of the applied rotation does any work. The published figure already accounts for this — it describes effective winding, not total rotation.
• Bi-directionalThe movement winds whichever way the rotor turns, so motion is converted more evenly and direction matters less. A winder alternating both ways suits virtually every automatic movement, which is why one setting can serve a mixed collection.